Sources and distribution of microplastics in China's largest inland lake - Qinghai Lake.

Microplastic pollution was studied in China's largest inland lake - Qinghai Lake in this work. Microplastics were detected with abundance varies from 0.05 × 105 to 7.58 × 105 items km-2 in the lake surface water, 0.03 × 105 to 0.31 × 105 items km-2 in the inflowing rivers, 50 to 1292 items m-2 in the lakeshore sediment, and 2 to 15 items per individual in the fish samples, respectively. Small microplastics (0.1-0.5 mm) dominated in the lake surface water while large microplastics (1-5 mm) are more abundant in the river samples. Microplastics were predominantly in sheet and fiber shapes in the lake and river water samples but were more diverse in the lakeshore sediment samples. Polymer types of microplastics were mainly polyethylene (PE) and polypropylene (PP) as identified using Raman Spectroscopy. Spatially, microplastic abundance was the highest in the central part of the lake, likely due to the transport of lake current. Based on the higher abundance of microplastics near the tourist access points, plastic wastes from tourism are considered as an important source of microplastics in Qinghai Lake. As an important area for wildlife conservation, better waste management practice should be implemented, and waste disposal and recycling infrastructures should be improved for the protection of Qinghai Lake.

Xiong X ，Zhang K ，Chen X ，Shi H ，Luo Z ，Wu C ... -  《-》

Microplastic abundance, distribution and composition in water, sediments, and wild fish from Poyang Lake, China.

Microplastic pollution in global aquatic environments has aroused increasing concern in recent years. In this study, the occurrence of microplastics in multiple environmental compartments was investigated in Poyang Lake, the largest freshwater lake of China. The abundance of microplastics was respectively 5-34 items/L for surface waters, 54-506 items/kg for sediments, and 0-18 items per individual for wild crucians (Carassius auratus). The distribution of microplastics in Poyang Lake varied heterogeneously in space, with the highest abundance being observed in the middle region of the lake for surface waters and in the northern region for sediments. Anthropogenic and topographic factors were speculated to be the major factors affecting the abundance and distribution of microplastics. The majority of the detected microplastics were found with a size of < 0.5 mm, with fibrous and coloured being the predominant characteristics. Polypropylene (PP) and polyethylene (PE) were the major polymer types of the selected plastic particles, indicating that domestic sewage and fishing activities might be the main sources of microplastics in the lake. No significant correlation was observed between microplastic abundance in surface water and sediment samples. Our results demonstrated the wide occurrence of microplastics in water, sediment and biota of the Poyang Lake, which may assist in extending our knowledge regarding microplastics pollution in inland freshwater systems.

Yuan W ，Liu X ，Wang W ，Di M ，Wang J ... -  《-》

Microplastics in Sediment and Surface Water of West Dongting Lake and South Dongting Lake: Abundance, Source and Composition.

Jiang C ，Yin L ，Wen X ，Du C ，Wu L ，Long Y ，Liu Y ，Ma Y ，Yin Q ，Zhou Z ，Pan H ... -  《-》

Microplastic pollution in Vembanad Lake, Kerala, India: The first report of microplastics in lake and estuarine sediments in India.

We present the first study of microplastics in the sediments of Vembanad Lake, a Ramsar site in India. Microplastics are emerging pollutants of increasing environmental concern with a particle size of <5 mm, which originate from successive degradation of larger plastic debris or are manufactured as small granules and used in many applications. The impact of microplastics pollution on the environment and biota is not well known. Vast data exist in the literature on marine microplastics while reports on freshwater ecosystems are scarce. In this context, to examine the occurrence of microplastic particles (MPs) in the Vembanad Lake, samples were collected from ten sites and processed for microplastic extraction through density separation. Identification of the polymer components of MPs was done using micro Raman spectroscopy. MPs were recovered from all sediment samples, indicating their extensive distribution in the lake. The abundance of MPs recorded from the sediment samples is in the range of 96-496 particles m-2 with a mean abundance of 252.80 ± 25.76 particles m-2. Low density polyethylene has been identified as the dominant type of polymer component of the MPs. As clams and fishes are the major source of protein to the local population, the presence of MPs in the lake becomes critically important, posing a severe threat of contaminating the food web of this lake. This study, being the first report from India on MPs in lake sediments, provide impetus for further research on the distribution and impact of this emerging pollutant on the biota of many aquatic systems spread across India.

Sruthy S ，Ramasamy EV 《-》

Microplastic pollution of lakeshore sediments from remote lakes in Tibet plateau, China.

Tibetan Plateau is known as the world's third pole, which is characterized by a low population density with very limited human activities. Tibetan Plateau possesses the greatest numbers of high-altitude inland lakes in the world. However, no information is currently available on the characteristic of microplastic pollution in those lakes within this remote area. In this work, lakeshore sediments from four lakes within the Siling Co basin in northern Tibet were sampled and examined for microplastics (<5 mm). Microplastics were detected in six out of seven sampling sites with abundances ranging from 8 ± 14 to 563 ± 1219 items/m2. Riverine input might have contributed to the high abundance of microplastics observed in this remote area. Morphological features suggest that microplastics are derived from the breakdown of daily used plastic products. Polyethylene, polypropylene, polystyrene, polyethylene terephthalate, and polyvinyl chloride were identified from the microplastic samples using laser Raman spectroscopy, and oxidative and mechanical weathering textures were observed on the surface of microplastics using scanning electron microscope. These results demonstrate the presence of microplastics even for inland lakes in remote areas under very low human impact, and microplastic pollution can be a global issue.

Zhang K ，Su J ，Xiong X ，Wu X ，Wu C ，Liu J ... -  《-》